Method of forming metal reflectors and apparatus therefor



Nov. 3, 1925- I 1,560,032

B. BART METHOD OF FORMING METAL REFLECTORS AND APPARATUS THEREFOR File dSept. 23, 1921 MaLa sup/ ow? AND CONDUCT/NC; Ran

INVENTOR Barf "ATTORNEY Patented Nov. 3, 1925.

UNITED STATES PATENT OFFICE.

BLASIUS BART, OF EAST ORANGE, NEW JERSEY.

METHOD or FORMING 1mm. mmorons AND APPARATUS 'rnnnnron.

Application filed September 23, 1921. Serial No. 502,679.

To all whom it may concern:

Be it known that I, B AsrUs BART, a citizen of the Republic ofSwitzerland, andof metallic reflector of the type now used inflash-lights, search-lights and similar light reflecting articles, andthe invention also relates to an improved method for forming suchreflectors and to an instrumentality for practicing the methodeconomically.

There is a demand in the market at presout for a form of reflector whichcan be manufactured cheaply and therefore with the use of a relativelysmall amount of material and with a minimum amount oflabor. Themanufacturing problem is further complicated by the requirement-thatsuch reflector be provided with a threaded socket for receivlng theelectric light blllb and some manufacturers of search-lights require anattaching flange or similar means for mounting the reflector in positionin the frame or other support.

It has been suggested in applicants copending application, Serial No.387 ,974, filed June 10, 1920 and Serial No. 387 ,975, filed June 10,1920 to form reflectors by spraying a solution of a silver salt onto apolished glass mold and to reinforce the thin film of reflecting metalby means of a backing of strengthening material such as copper,electrolytically deposited on the film of reflecting material whilepositioned on the mold. It is a vital requirement of this process thatthe glass mold be chemically clean and highly polished in order toproperly receive the layer of reflecting material. This is particularlytrue when the material is nascently reduced silver.

Accordingly, one of the objects of the present invention is to providefor the formation of a reflector by practicing the method outlined withits necessity for a polished mold and at the same time form the requiredsocket and attaching flange dedeposit receiving surface is continuouswithoutprojections and thus capable of being,

formed initially and also capable of being polished from time to timeas'is required:

by the practicing of the method outlined. Where the socket is tobeformed the mold is provided with an opening extending therethrough andwhich of course does'not interfere with the polishing process. It willbe understood that a mold provided with the necessary projections toform sockets, flangesand the like, would interfere with the polishingoperation of the mold. The socket required is preformed preferably as astamping from sheet metal, is positioned at the opening and incidentallyconstitutes part of the means for mountin the mold in position. With themold held by means engaging the opening and with the socket located inposition the suggested process of depositing the silver on the polishedmold is practiced. Afterwards the mold with its silver depositsurrounding the socket is positioned in an electrolytic tank and in thiscase it is further suggested that the support of the mold constitute thecon ductor for carrying current to the mold. A layer of backeningmaterial, such ascopper is deposited on the sprayed silver layer whichcopper deposit is continued across the socket, thus constituting a meansfor securing the socket permanently in place in the finished reflector.For the purpose of form ing-the attaching flange it is suggested that anoutliningrim be demountably fitted to the previously polished surface ofthe mold and the electrolytically deposited backing be continued acrossthe rim to form the re,- quired outwardly projecting fastening means.

Referring to the apparatusfeature of the disclosure, an object of theinvention is to provide a simple form of mold construction in which thedifferent parts are readily demountable, particularly for the purpose ofcleaning and polishing the glass mold which forms a part of theconstruction, and at the same time to provide a single piece ofapparatus which can be utilized with its assembled parts during theactof depositing the reflecting material, and which can also be utilizedto support and convey current to the parts of the electrolytic tank'during the step of forming the backing layer.

include projecting parts, such as an electric light bulb mounting socketand a securing flange. It is also required that the reflec-' tors beformed of a comparatively small amount of material; that all of thereflectors shall be uniform in appearance and that they be constructed,without necessity for any refined machining or expensive manual laborin the process of forming the same.

Referring to theaccompanying drawings there is disclosed a preferredembodiment of the physical aspects of the invention.

Fi re 1 is a vertical sectional view taken axial y through one of a setof mold structures showing the completed reflector in full outline,after it has been rotated fromits dotted line position in theelectrolytic tank; an

Figure 2 is a sectional view taken axially through a finished reflectorslightly modi-" fied from the form shown in Figure 1 removed from themold construction.

In the drawings, there is shown an electrolytic tank 10 containing anelectrolyte 11 on which tank is positioned a combined mold support andconducting rod 12. It is understood that in electrolytic work the tankis of some material length and the single support 12 has a plurality ofmold structures positioned along the length thereof. These structuresare designed to be, turned down into the electrolyte as shown in dottedlines or to be secured in their upright position shown in Figure -1during the act of depositing the silver on the molds. However, a usualpractice is to mount the support 12 on a work table during the edge 24of the glass mold is outlined by a rim 25 of non-conducting materialpreferably bakelite. The inner periphery 26 of the'rim is curved andshaped to snugly fit the glass mold and thus provide a'closed jointbetween the glass mold and the bakelite rim. The side 27 of the rimadjacent the metal receiving portion of the mold has a width and isshaped to correspond to the width and shape of the securing flange 28desired on the completed article.

The device thus far described may be regarded as a complete reflectorwith a single lamp screwed into the socket at the apex of the same.

Under some conditions, such for instance, as where it is desired tomount a dim lamp in the reflector an additional socket 29 is secured inplace usually between the apex and periphery of the reflector. In orderto show a form of cap diiferent from the cap 21, the socket 219 is notthreaded and is simply an open end tube. For the purpose of disclosing ameans for securing either socket or cap in-=place by a means differentfrom the plug 16 there is disclosed a bolt 30 passed through the moldand secured in place by a nut 31. The bolt is provided with a mushroomhead 32 which bears at its central part on the outer end of the tubularlamp socket 29 and has a peripheral shoulder 33 which acts to preventthe copper backing from coming up to the top of the socket during theelectrolytic depositing' step of the method.

In this form of the lamp mounting it may be considered that the lamp issecured in process of assembling the mold and depositthe socket29 in anyusual manner, for ining the silver on the same. A collar 14 is fixed tothe rod 12 and is provided with a threaded bore 15 into which isinserted one end of a brass plug 16, which projects laterally from thesupport 12. The plug is provided adjacent its opposite end with a stopshoulder 17 and the portion beyond the shoulder is screw threaded asshown at 18. A semi-spherical hollow glass mold 19 is provided at itsapex with an opening 20, of a size to receivethe threaded end of theplug. The'parts are so proportioned that the mold is disposed inposition with the .tion 18 of the plug.

part thereof surrounding the opening resting on the stop shoulder 17 andthe mold is temporarily secured to the plug 16 by means of a cap orsocket 21 screwed onto the por- The cap is provided with an outstandingflange 22 which bears on the outer convex side 23 of the glass mold toforce the same into engagement withthe stop shoulder 17. The threadedsocket is preformed preferably by stamping from sheet metal and has asize and pitch of thread to accommodate whatever type of electric lightbulb socket'it is desired to screw into the completed reflector.' Thefree stance, the socket may be the usual casing of the lamp bases now ingeneral use.

The outer convex face of the glass mold is polished over its entiresurface either manually or by means of a machine constructed for thispurpose. It is appreciated that the surface of the mold polished iscontinuous and therefore is susceptible of being against the stopshoulde' and bringing the,

flange :of the socket into bearing engagement with the polished portionof the glass mold surrounding the opening. The bakelite rim is thendisposed in position and forced into snug engagement with the glassmold.

A mixture of silver-salts and a reducing agent therefore is sprayed ontothe exposed portion of the polished glass in the manner moreparticularly defined in the above identified applications. The silverdeposit is continued up the threads of the flange on the socket and upto the flange forming the rim. When the desired thickness of silverdeposit is formed the assembled structure is disposed in theelectrolytic tank. Preferably the support 12, collar 15, plug 16, areformed of some conducting material such as brass and thus constitute ameans for conveying current to the parts to be coated as is usual inelectrolytic operations of this character.

It is appreciated that one homogeneous layer of backing material, suchas copper, is formed and that this backing extends continuously andintegrally across the rim to form the securing flange, across the silverdeposit to reinforce the sameand across the socket to. secure the socketpermanently in b position relative to the reflecting surface in thecompleted reflector.

Having thus described my invention, I"

claim:

1. In the art of forming a metallic reflector with a threaded socket forreceiving the light bulb, the method which consists in assembling aglass mold with an opening therethrough, insert-ing a threaded plug insaid opening, screwing a preformed threaded socket onto the plug andforcing the plug into bearing engagement with the part of the moldoutlining the opening, depositing a layer ofsilver on the mold,extending thelayer up to the preformed socket and covering the silveredsurface and the socket with a backing of copper electrolyticallydeposited togive strength to the reflector and to secure the preformedsocket in place.

2. In the art of forming-a metallic reflector with a threaded socket forreceiving the light bulb and with an outlining flange, the method whichconsists in assembling a glass mold with an opening therethrough,inserting a threaded plug in said opening, screwing a preformed threadedsocket onto the plug and forcing the plug into bearing engagement withthe part of the mold outlining the opening, positioning a bakelite rimabout the glass mold in spaced relation to the socket, depositing alayer of silver on the mold, extending the layer up to the preformedsocket and covering thesilvered surface, and the socket with a backingof copper electrolytically deposited to give strength to the reflectorand to secure the preformed socket in place, the socket and the side ofthe rim adjacent the silvered surface with a layer of copperelectrolytically deposited and separating the reflector thus formed fromthe glass mold and the rim.

3. In the art of forming a concaved metallic reflector with a threadedsocket, the

method which consists in polishing. a glass mold over all parts whichare to define the reflecting surface,positioning a preformed socket,said layer being continuous across the joint between the re ecting metaland the socket whereby the backing acts to secure the socket in place.

In the art of forming'ametallic reflector with an outwardly extendingflange at its free edge, the method which consists in polishing theouter surface of a glass mold, fitting a rim of non-conducting materialto the polished surface to form a close joint therewith, depositing alayer of a reflecting metal on the polishedglass surIace,electrolytically forming a layer of a metallic acking on the reflectingsurface, on therim and across the joint therebetween, the portion on therim forming the flange and the portion on the reflecting layer acting tostrengthen the same,'severing the formed backing from the rim andremoving the glass mold from the finished reflector.

5. Inthe the art of forming an object which includes a non-continuoussurface and an electrolytically deposited layer, the method whichconsists in providing a mold with a continuous surface capable of beingpol- .isheol, polishing said surface, depositing a "trolyticallydepositing a layer of metal over the portion previously deposited layerand over the non-continuous surface.

6. In the art of preparing a mold for a a metallic reflector whichincludes a threaded socket for receiving the light bulb, the methodwhich consists in assembling a glass mold with an opening therethrough,inserting a threaded plug in said opening, screwing a preformed threadedsocket onto the plug and forcing the plug into bearing engagement withthe part of the mold outlining the opening, the jointure between saidpart of the mold and the socket adapted to be covered with a layer ofmetal.

7. In the art of preparing a mold for use in forming a metallicreflector electrolytically, the method which consists in'asseinbling aglass mold with an opening therethrough, positioning at said opening apreformed member which is to constitute a pa rt" the method whichconsists in forming a glass mold polishing a face of the mold,positioning on the polished face of the mold a preformed member which isto constitute a part of "the finished article, subjectin" said polishedsurface of the mold and said member to acoating of metal depositedthereon to form the portion of the article defined by said polished faceand to secure the" preformed member in place as part of the article soformed. 9. In the art of forming a metallic rcflector, the method withconsists in providing a glass. mold having a deposit receiving surfacecontinuous from edge to edge free of projections and capable of beingpolished, positioning on said surface a projection to modify the effectof the mold on the resulting reflector. depositing on the mold a facelayer of metal and electrolytically depositing on said face layer and oni said projection a continuous backing layer .of metal. 1

10. In the alt of forming a metal article by electrolytic deposition,the method which consists in providing a mold, mounting on the mold apreformed object designed to modify the effect of the mold 011 theresult-- ing article and subjecting both the mold and object to a layerof metal deposited thereon electrolytically and removing the mold while3 article and said permitting the objectto remain as part of thearticle.

11. In a device of the class described, the combination of a supportincluding a threaded plug provided with a stop shoulder, a glass moldprovided' with an opening for receiving the plug when engaging saidshoulder, apreformed socketadapted to be temporarily threaded on theplug and acting to clamp *the mold to the support,'said mold and plugcoacting to define thesha e of the finished lu a apted to be unscrewedfrom the fi iiis ed article leaving the socket in place.

12. [In a device of the class described, the combination of a glass moldhaving a surface capable of being polished and having an openirigextending through the polishable surface and means engaging said openingfor supporting the mold in an. electrolytic tank.

13. Ina device'of the class described, the

' combination of a glass mold having a substantially semisphericalconvex surface capable of being polished and having an opening at theapex, a support extending through the opening and adapted to hold thepolished mold in position to receive a metallic deposit on the polishedsurface.

14. In a device of the class described, the combination of a glass moldhaving a. substantially semisplierical convex surface capai bleof beingpolished and having an opening at the apex, a supportextending-throughthe opening and adapted to hold the polished mold inposition to receive a metallic deposit on the polished surface, saidsupport constituting an electric conductor adapted to position the moldin an electrolytic tank and to carry an electric current to the same.

15. In a device of the class described, the

by said plug, means for temporarily securand a reflector ing the mold tothe plu formed on said mold, sai' reflector including a part of saidsecuring means.

17. In a device of the class described, the

combination of a plug having a stop shoulder and a threaded portionadjacent the shoulder, a mold engaging said shoulder, a

socket threaded on the plug and bearing-on the mold to secure the sametemporarily to the plug, a layer of reflecting material on the mold anda backing layer on the reflecting material extending over the socket tosecure the same permanently to the layer of reflecting material.

18. In a device'of the class described, the combination of a plug havinga stop shoulder and a threaded ,portion adjacent the shoulder, a mold enaging said shoulder, a socket threaded on the plug and bearing on themold to secure the same temporaril to the plug, a layer of reflectingmateria on v the mold, a backing layer on the reflecting materialextending over the socket to secure the same permanently to the layer ofreflectin material and means encircling the inold or defining the shapeof the backing a er.

l9. In a device of the class described, the combination of a semi-sherical glass mold having an-opening at t e apex, a support positionedin said opening and a rim encircling themold adjacent its free edge,said rim and support being readily removable from the lass moldto permitthe same to be polished.

20. In a device of the' class described, the combination of asemi-spherical glass mold having an opening at theapex, means forsecuring a threaded socket in position facing said opening, a supportositioned in said openings and a rim encirc ing the mold adjacent itsfree edge, said rim and support being readily removable from the glassmold to permitthe same to be polished.

21. In a device for forming a metallic reflector, the combination of aconducting rod, a metallic collar secured to the rod, ametallic plugscrewed into the collar, a glass mold carried by the plug and a, socketthreaded on said plug and engaging the mold.

22. In a device for forming a metallic reflector, the combination of aconducting rod, a metallic collar Secured to therod, a metallic plugscrewed into the collar, aglass mold carried by the plug, a socketthreaded ,on said plug and engaging the mold and a rim outlining thefree edge of the mold, said mold rim and socket coacting to define theshape of the completed reflector.

23. A glass mold for use in forming metallic reflectors, said moldprovided with a surface adapted to be polished, and provided with anopening extending there through and through said surface.

Signed at New York city, in the county of New York and State of NewYork, this 12th day of September, A. D; 1921.

v BLASIUS BART.

